Embolised mesothelial cells in a tracheobronchial lymph node associated with idiopathic chylopericardium in a dog

A 5·5‐year‐old male castrated Bernese mountain dog presented with respiratory difficulties and was diagnosed with haemorrhagic pericardial effusion which transformed into chylopericardium. Thoracic duct ligation and subtotal pericardiectomy in combination with biopsy of an enlarged tracheobronchial lymph node were performed. Multiple clusters of mesothelial cell emboli were observed in the subcapsular sinus of the lymph node. No causative agent for the pericardial effusion could be identified, suggesting that this is a case of mesothelial cell embolisation associated with idiopathic ‐chylopericardium in a dog.